Injection valve tip



lam. 26, 1937. R. H. HOADLEY 2,068,673

' INJECTION VALVE TIP Filed Feb. 9, 1935 Y i=5. .El,

1H mpsbml'ron W -HodLey ATTORNEY Patented Jan. 26, 1937.

UNITED STATES PATENT OFFICE INJECTION VALVE TIP Raymond B. Hoadley,Bronx, N. Y.

Application February 9, 1935, Serial No. 5,877

' Claims. (01. 299-1071) The present invention relates to valve tips forDiesel engines.

In certain types of Diesel engines the fuel oil is injected through anozzle at very high pressure 5 produced by suitable pumps and under thecontrol of valve gear. The valve tips heretofore in common use have beenmade of steel and have a hollow conical tip provided with asuitablenumber of very small fuel metering holes drilled to through the tip tothe seat for the valve stem, the holes'being opened and closed by thevalve. These tips lose efficiency very rapidly on account of theclogging of'the nozzle holes, which appears to result from a carbondeposit formed by the incomplete combustion of the residual oil in thetip. The carbon forms a crust which interferes with the injection offuel and may eventually clog the entire hole of the nozzle so that theengine does not receive the designed charge of fuel.

The present invention contemplates the provision of injection valve tipsof an improved form and operation whereby the useful life of the tip isgreatly extended, the power which may be had from the engine increased,and whereby the engine speed may be controlled through much wider limitsthan with ordinary nozzles.

In carrying out the invention, the tip is redesigned so that the fuelpasses through nozzle openings of stepped cross section. The inner partof the nozzle opening is drilled to the small diameter to control thequantity of fuel admitted. This very small hole leads into a largerdiameter passageway through which the jet is projected.

These larger holes act as a shroud or sheath and protect the orificesfrom clogging by carbon.

The invention also contemplates the disposition of the nozzles so as toproduce a flatter spray than has been customary whereby an improvedcombustion of the fuel takes place, and to produce a cushioning effectwith no appreciable rise in temperature of exhaust gases.

Other and further objects of the invention wi appear as the descriptionproceeds:

The accompanying drawing shows, for purposes of illustrating the presentinvention, one of the many embodiments in which the invention may takeform, it being understood that the drawing is illustrative of theinvention rather than limiting the same. In the drawing:

Fig. 1 illustrates in section and at an enlarged scale a typical valvetip such as heretofore in use; Fig. 2 is a fragmentary view at a stillfurther enlarged scale showing the orifice in common use andillustrating how it is clogged by carbon;

7 opening.

Fig. 3 is a view similar to Figure 1 of the preferred form of tipembodying the present invention; 1

Figs. 4 and 5 are side and end elevational views of the tip shown inFigure 3; and 5 Fig. 6 is a fragmentary enlarged view through theorifice of the tip of Figure 3.

The common valve tip of Figures 1 and 2 is in the form of a single pieceof steel I!) turned to the shape shown and drilled to provide a num- 10her of orifices II, which meter the fuel and lead to a valve seat It.These orifices are opened and closed by a valve stem l3 and suitablegear not shown. The orifices are in the form of small holes of from0.008 inch to 0.015 inch in diameter 15 depending on horse power ofengine. These tips usually have a conicalpoint of an angle of about andthe orifices are drilled at an angle of about 72 to with face of tip,with the result that the spray from the tip is confined into a 20 narrowcone of about 72. Examinations of tips which have seen service usuallyshows a heavy, hard carbon deposit or crust about the nozzle This isindicated at- I4 in Figure 2.

It appears to come from the burning or breaking 5 down of the exposedsurface of the droplet oil which is held in the orifice of the nozzle.The engine power and ease of starting andhandling is seriously impaired.Due to the clogging of the orifices the cylinders work unevenly. Thispro- 30 motes a smoky exhaust due to poor and incomplete combustion. Thebuilding up of this carbon I deposit is progressive and it interfereswith the discharge of the fuel, both as to quantity and its atomization.35

In the construction of Figure 3, embodying the present improvements, thevalve tip is made of two turnings. The outer oneor shroud I5 is ofbronze which has high thermal conductivity and istherefore quicklycooled by the air taken into 40 the cylinder. It therefore expands andcontracts with each cycle. The inner member I6 is of steel for strength.These. members are made accurately to-size so that when the steel insertis forced into the sheath the joint is oil tight. The 45 steel liner i5is adapted to receive the valve stem l1 and has a seat l8 for the valvestem. The

end of the tip is turned to have a cone of The outer sheath is providedwith a plurality of comparatively large holes, about 1 5' inch in 50diameter as indicated at l9. These holes are preferably drilled beforethe steel insert is forced in place. The fuel orifices 20 are drilledvery carefully so as to proceed fromthe centers of the larger holes.These orifices are of the proper 55 diameter for the quantity of fuelthey are to supply and are preferably drilled at about 50 to the tipaxis. The spread of the jet is therefore approximately 50" from the axisof the tip. This spreads the jets further from the axis than usual andproduces a widely spreading fan-like fiame. It avoids the sudden blow towhich the pistons and connected parts are usually subjected and has beenfound to materially reduce the noise of the engine and the wear on thebearings.

The stepped orifice is similar to a mouthpiece or pipe having a suddenenlargement. There is sinuous flow along the pipe, the stream suddenlyenlarging to fill the pipe. The fuel is, however, sprayed out withoutloss of volume or material loss of energy, except for eddy motions.\Vhatever fuel is left in the passage after an explosion, with anycontamination by carbon, is washed away by the next charge so that cleanoil is always being passed over the surfaces.

Experience with the fuel tips herein described show that the engineoperation is greatly improved, both as to maximum power available andflexibility of control. The exhaust gases are clear and free of smoke orsoot, and the exhaust temperature low. While of general use in Dieselengines, they have been found to be of especial advantage for use onmarine engines where it is important to avoid shut down for repairs, andwhere maneuverability of the ship is necessary.

It is obvious that the invention may be embodied in many forms andconstructions within the scope of the claims, and I wish it to beunderstood that the particular form shown is but one of the my forms.Various modifications and changes being possible, I do not otherwiselimit myself in any way with respect thereto.

What is claimed is:

1. In a Diesel engine an injection valve tip having an insert providedwith small diameter orifices through which the fuel is injected into thecylinder and an outer sheath provided with means about the orifices toprevent the incomplete combustion of fuel adjacent the orifices wherebyclogging of the orifices by carbon is prevented.

2. A Diesel engine injection tip having an outer sheath and an insert,the insert having small diameter fuel metering passages, the sheathhaving co-axialperforations of substantially larger diameter to provideit with cylindrical openings which shroud and protect each of the fuelpassages.

3. A tip as claimed in claim 2, characterized in that the insert is ofhard metal to withstand the action of the valve stem and the sheath isof a metal having a greater temperature conductivity.

4. A tip as claimed in claim 2, wherein the sheath perforations areapproximately six times the diameter of the metering passages.

5. A Diesel engine injection tip having an outer bronze sheath and asteel insert, the insert having small diameter fuel metering passages,the

sheath having co-axial performations of substantially larger diameter toprovide it with cylindrical openings which shroud and protect each ofthe fuel passages.

RAYMOND H. noarinn r.

